   (remove-pages! [_ state page-ids]))
 
 (defprotocol ColumnDropTarget
-  (accept-drop!  [_ state pages]))
+  (accept-drop!  [_ state pages target-idx]))
 
 (defrecord InboxColumnSource [id]
   ColumnSource

(defn ^:private mark-page-selected
  "Assocs {:selected? true} to `page' if `selected-pages'
  contains (:id page). Used in `index-column'."
  [selected-pages page]
  (assoc page :selected? (contains? (set selected-pages) (:id page))))

(ui/defcomponent inbox-column [[state column] owner opts]

               {:opts {:enable-rotate? true}})]))

(defn ^:private get-transfer-data [e key]
  (or (some-> e.dataTransfer
              (.getData (name key))
              (read-string))
      (js/console.warn "Couldn't read transfer-data for key:" (pr-str key))))

(defn ^:private column-drag-start
  "Called from `inbox-column' when `dragstart' event is fired. Manages
